The present invention relates to a packet banding device.
In particular, the present invention relates to a device for applying adhesive bands to parallelepiped packets.
The present invention is especially suitable for use on packing machines, particularly cigarette packing machines, to which the following description refers purely by way of example.
In the tobacco industry, it is necessary at times to apply adhesive bands, usually in the form of inland revenue or advertising strips, to the outside of the packets. This is normally done using devices comprising a feedbox from which the bands are withdrawn one by one and fed successively along a path having at least one portion in common with the path along which the packets are fed. Prior to reaching the common portion of the path, along which the bands are applied to the packets, the bands are fed through a gumming device by which the packet mating surface of the band is coated with adhesive.
Though satisfactory under normal operating conditions of the packing machine, known devices of the aforementioned type present several drawbacks in the event the packing machine is slowed down or arrested. In fact, mainly on account of its size, the gumming device can seldom be set up immediately upstream from the point at which the bands are actually applied to the packets along the common portion of the path, so that, at any given time, unused gummed bands are invariably present between the gumming device and the point of application.
As stoppage of the packing machine is normally accompanied by simultaneous stoppage of the hand feed device, the gummed bands, with the gum already drying, must be extracted, even if not rejected, by means of a relatively complex, time-consuming operation prior to restarting the packing machine.
Moreover, in the event of an emergency requiring stoppage of the gumming device, the inertia of the machine following the stop signal results in the production, downstream from the gumming device, of a certain number of nongummed bands posing the same difficulties as described above.